When intending to form a linear topology network using wireless transmission apparatuses operated in an ad-hoc manner, the wireless transmission apparatuses may be linearly disposed. The disposed wireless transmission apparatuses form communication links with peripheral wireless transmission apparatuses communicable in an ad-hoc manner, thereby configuring the entire network. In this configuration, when considering the characteristics of the linear topology network, if one communication link loses communication capability, data from any one side cannot be transferred to the other side, based on the node of the communication link, such that the entire network is not formed. Therefore, considering the case where the communication capability of the entire network is lost due to the communication capability loss of the specific node, a need exists for a network recovery function for reconfiguring a network other than a node losing the communication capability. To this end, the wireless transmission apparatuses are disposed so that the communication coverage of the wireless transmission apparatuses overlaps with each other.
The formation, operation, and recovery method of the initial network may be varied according to a kind of antenna used by the transmission apparatus. The antenna may be largely classified into an omni-directional antenna and a directional antenna according to a kind of antenna used up to now.
When forming and operating the linear topology network using the wireless transmission apparatus using the omni-directional antenna, the wireless transmission apparatuses should be densely disposed in consideration of the network recovery, as compared to the case of using the directional antenna. This increases costs of network configuration. In addition, in order to replace the communication range of the node losing the communication capability, the peripheral transmission apparatuses increase the transmission output to recover the network, thereby increasing the power consumption. Further, when the transmission is performed at higher power through the omni-directional antenna, the interference having an effect on other nodes is more increased.
When the linear topology network is formed by using the wireless transmission apparatus using the directional antenna and is operated, a separate synchronization process to synchronize directivity for transmission and reception between the transmission apparatus and the peripheral transmission apparatuses should be continuously performed during the network operation. This wastes the power of the transmission apparatus having a limited power and a operation power and increases the calculation load. Further, in the case of using a steerable directional antenna in order to find direction other than the direction defined at the early time of forming the network during the network recovery, it is not suitable for the transmission apparatus having a limited operation power and it is difficult to make the transmission apparatus small. Further, in the case of using a non-steerable directivity antenna the directivity cannot be physically steered, such that the network cannot be recovered